Satellite systems for worldwide navigation (Global Navigation Satellite System GNSS, satellite navigation system for short) are used for position determination and navigation on the ground and in the air. In order for a receiver to determine a given position, navigation messages are transmitted in the GNSS via the satellite signals. In the European GNSS Galileo (below also referred to as the Galileo system or Galileo for short), which is being set up at this time, however, the current specification only provides for very few bits for future expansions, which, of course, limits any later expansion of the Galileo system by new services and additional information.